The Four Horsemen Of The Apocalypse Are Saddling Up

Twenty years ago scientists met at the Earth Summit in Rio to examine the climate and ecology of the Earth and man´s impacts. Two decades later 17 prominent ecologists have released a paper summarizing the evidence of the 1000´s of ecological studies undertaken in since 1992.

In short they decided that the evidence is overwhelming and consistent. The danger of a catastrophic ecological crash is looming and is far more immediate than previously believed. In some areas of the world collapses are already happening.

Coauthor Elizabeth Hadly from Stanford University said, “We may already be past these tipping points in particular regions of the world. I just returned from a trip to the high Himalayas in Nepal, where I witnessed families fighting each other with machetes for wood — wood that they would burn to cook their food in one evening. In places where governments are lacking basic infrastructure, people fend for themselves, and biodiversity suffers. We desperately need global leadership for planet Earth.”

Coming from Chile, Canada, Finland, the United Kingdom, Spain and the United States, the authors of this paper initially met at the University of California Berkeley in 2010 to hold a trans-disciplinary brainstorming session.

They reviewed scores of theoretical and conceptual bodies of work in various biological disciplines in search of new ways to cope with the historically unprecedented changes now occurring on Earth.

In the process they discovered that:

Human-generated pressures, known as global-scale forcing mechanisms, are modifying Earth’s atmosphere, oceans and climate so rapidly that they are likely forcing ecosystems and biodiversity to reach a critical threshold of existence in our lifetime.

Global-scale forcing mechanisms today “include unprecedented rates and magnitudes of human population growth with attendant resource consumption, habitat transformation and fragmentation, energy production and consumption, and climate change,” according to a statement by Simon Fraser University (SFU).

Human activity drives today’s global-scale forcing mechanisms more than ever before. As a result, the rate of climate change we are seeing now exceeds the rate that occurred during the extreme planetary state change that tipped Earth from being in a glacial to an interglacial state 12,000 years ago. You have to go back to the end of the cataclysmic falling star, which ended the age of dinosaurs, to find a previous precedent.

The exponentially increasing extinction of Earth’s current species, dominance of previously rare life forms and occurrence of extreme climate fluctuations parallel critical transitions that coincided with the last major planetary transition.

When these sorts of perturbations are mirrored in toy ecosystem models, they tip these systems quickly and irreversibly.

The authors recommend governments undertake five actions immediately if we are to have any hope of delaying or minimizing a planetary-state-shift. Arne Mooers, an SFU biodiversity professor and a co-author of this study, summarizes them as follows.

“Society globally has to collectively decide that we need to drastically lower our population very quickly. More of us need to move to optimal areas at higher density and let parts of the planet recover. Folks like us have to be forced to be materially poorer, at least in the short term. We also need to invest a lot more in creating technologies to produce and distribute food without eating up more land and wild species. It’s a very tall order.”

“Much as the consensus statements by doctors led to public warnings that tobacco use is harmful to your health, this is a consensus statement by experts who agree that loss of Earth’s wild species will be harmful to the world’s ecosystems and may harm society by reducing ecosystem services that are essential to human health and prosperity,” said Bradley Cardinale, an associate professor at the U-M School of Natural Resources and Environment and in the Department of Ecology and Evolutionary Biology.

“We need to take biodiversity loss far more seriously–from individuals to international governing bodies–and take greater action to prevent further losses of species,” said Cardinale.

The authors note that studies of small-scale ecosystems show that once 50-90 percent of an area has been altered, the entire ecosystem tips irreversibly into a state far different from the original, in terms of the mix of plant and animal species and their interactions. This situation typically is accompanied by species extinctions and a loss of biodiversity.

“No one can agree on what exactly will happen when an ecosystem loses a species, but most of us agree that it’s not going to be good. And we agree that if ecosystems lose most of their species, it will be a disaster,” said Shahid Naeem of Columbia University, one of the co-authors. “Twenty years and a thousand studies later, what the world thought was true in Rio in 1992 has finally been proven: Biodiversity underpins our ability to achieve sustainable development.”

Human actions are dismantling Earth’s natural ecosystems, resulting in species extinctions at rates several orders of magnitude faster than observed in the fossil record. Even so, there’s still time–if the nations of the world make biodiversity preservation an international priority–to conserve much of the remaining variety of life and to restore much of what’s been lost, according to Cardinale and his colleagues.